index_update(x, idx, y, indices_are_sorted=False, unique_indices=False)¶
Pure equivalent of
x[idx] = y.
Returns the value of x that would result from the NumPy-style
x[idx] = y
Note the index_update operator is pure; x itself is not modified, instead the new value that x would have taken is returned.
x[idx] = y, if multiple indices refer to the same location it is undefined which update is chosen; JAX may choose the order of updates arbitrarily and nondeterministically (e.g., due to concurrent updates on some hardware platforms).
x – an array with the values to be updated.
idx – a Numpy-style index, consisting of None, integers, slice objects, ellipses, ndarrays with integer dtypes, or a tuple of the above. A convenient syntactic sugar for forming indices is via the
y – the array of updates. y must be broadcastable to the shape of the array that would be returned by x[idx].
indices_are_sorted – whether scatter_indices is known to be sorted
unique_indices – whether scatter_indices is known to be free of duplicates
>>> x = jax.numpy.ones((5, 6)) >>> jax.ops.index_update(x, jax.ops.index[::2, 3:], 6.) array([[1., 1., 1., 6., 6., 6.], [1., 1., 1., 1., 1., 1.], [1., 1., 1., 6., 6., 6.], [1., 1., 1., 1., 1., 1.], [1., 1., 1., 6., 6., 6.]], dtype=float32)